One of the moste common arguments for interdisciplinarity especially in the sciences is that a lot (probably even the most) of everyday tasks need knowledge, skills or competencies from different domains and are interdisciplinary per se. Some researchers even state that this is also true for most scientific problems. The consequence could be that scientific competences need to be developed in interdisciplinary contexts in order to be linked: e.g. the concept of energy plays a crucial rule in physics, biology and chemistry - some students might to tend to think that the energy their chemistry teacher is talking about is something totally different than what their physics teacher means by energy. There are also a lot of research projects in science education highlighting the advantages of interdisciplinary approaches. Also the German educational system is shifting in some federal states from teaching the sciences solitarily (physics, chemistry, biology in different subjects) to general science courses.

It seems that interdisciplinarity in the sciences is somehow modern and makes sense. But there are two major arguments against it in my point of view.

First con-argument: I am according with the philosopher Konrad Liessmann who said that the different domains took centuries to develop their own methods and there own traditions. it could have been differently, but these traditions do have a certain value. By mixing domains in new subjects you create new domains with no tradition, no culture and most importantly domains with no certain methods. The methods a physicist needs to solve problems have shown their potential for centuries, so did the methods a biologist needs - but for a "general scientist"? We just do not know. This is even more important if you mix domains like politics and history, maybe the sciences are more similar.

Second con-arument: That leads to another argument against it. Teachers who feel uncertain about a topic tend to avoid these topics. We can observe this in the "general science" subject. Most teachers in this subject major in biology, they feel uncertain about their skills in physics - and the consequence is that they concentrate on biology. That of course is very understandable from a personal point of view but it might lead to a less profound education in physics. One could say: these teachers know the tradition and the culture of their subject, they feel as biologist - a consequence of the new subject with uncertain tradition and methods is that they transmit these biology culture an this newly created subjected. That is a problem for physics and maybe even chemistry.

If you ask me what I am thinking I would say that solving interdisciplinary problems is important for motivation and for a better linked knowledge. But the basis of interdisciplinarity is disciplinarity. We should understand the traditions and methods of the different domains as important parts of the domains. We should also understand their traditions and methods as a part of our cultural heritage and I sometimes feel that we underestimate that.

Thanks for this first answer.

You said that some experiments have been conducted (and intended to revel "advantages of interdisciplinary approaches"). This is exactly what I am looking for: scientific articles (pro or cons, of course). Can you give me some references?

Élisabeth Bautier, French sociolinguist and researcher in educational sciences, focuses on inequalities. She states that interdisciplinary can dig the gap between low level and high level students. Stéphane Bonnéry, an other French educational researcher, thinks that interdisciplinary projects for k16-19 pupils are either too simple or too difficult... I thank you for giving me better cons arguments that these ones... I mean:

• Bauthier's argument can be state for basically any pupils work (as flute classes), and especially in group works IF they are miss-conduct by the teacher. A contrario, if groups are properly made (with a good range of level between members), then I think that it has been showed by studies that inequalities decrease. So this argument is an "group work teaching formation" argument, which have to be heard but it is not specific to the interdisciplinary matter.
• Bonnéry's argument is just an argument form authority. And as I don't know him, I will take it as a logical fallacy.

As a pro-interdisciplinary argument that I heard is the high level of enthusiasm of pupils, which I think for k11-16 is fundamental (see 2. below). Also it can help making sense of basic-concept, especially math concept like measuring (centimeters in math are the same that in technology classes -- yes, it is that bad here.). But those two arguments are just feedbacks from teachers, not reseach studies. That why I would like to read the ones you talked about.

Ok, now, let me discuss your arguments. I think that both are true BUT irrelevant for French reform case because in that reform:

Form 1. and 2., we can be confident that topic cultures and methodologies are not at stake. And that is important. From 1. and 3., we can say that as teachers will design their projects they shall be ok with its and they shall perform their skills in each's domain of expertise. That is a relief.

I think that the fact that this reform concerns early teenagers (with all the specificities of this age in terms of social behavior, relation with education, cognition development) is an important point. It might be a good thing for interdisciplinary but it is only a thought, not a scientific argument.

You said that German educational system introduced some interdisciplinary. For how long has it been? How does it work? What are the feedbacks (from researchers)? Please if you have a hand on some scientific papers, feed me! ;)

PS: I am a math teacher, not a researcher.

http://www.slate.fr/story/101073/ecole-debat-interdisciplinarite

Dear Hector,

first of all: I would not consider myself to be a "real expert", but as a researcher in science education (and a former physics teacher) I know some studies. In my point of view, two approaches are really important to understand the effects of interdisciplinarity.

The first approach should be some one of integrated curricula:

• Hurley (2001) report that integrating mathematic and science programs leads to rather small effects with respect to achievement and mathematics benefits much more than science (Hurley, M (2001). Reviewing integrated scinece and mathematics: The search for evidence and definitions from new perspectives. School Science and Mathematic 101(5), 259). 
• Hartzler's (2000) meta-studie also reports about small effects. The most important finding in my opinion is that it seems to be far more effective in elementar schools than in high schools. My interpretation is that the topics in high school are to sophisticated - maybe Bonnéry's argument is not that wrong after all and the projects that are too easy for high-school students work with younger students.(Hartzler, D. (2000). A meta-analysis of studies conducted on integrated curriculum programs and their effects on student achievement, unpublished and cited from Hattie, J. (2009) Visible learning. London: Routledge)

The second important approach deals with effects on motivation and interest. Context oriented teaching is a very common approach. For most interdisciplinary teaching projects a context is a starting point, often an everyday context. E.g. Fechner (2009) showed in a high-quality study that context-oriented teaching in chemistry has impact on situational interest. The effects on achievement are rather small. (Fechner, S. (2009). Effects of context-oriented learning on student interest and achievement in chemistry education. Berlin: Logos).

In the way you describe the French reform it seems to be a moderate approach. In Germany I sometimes fear that the real reason for interdisciplinarity is that it it cheaper because you can e.g. use biology teachers to teach physics. It is rather new and there is no evidence that I am aware of in Germany. E.g. in Bremen, the federal state I am from, interdisciplinary science courses have been established just about 5 years ago and just for the first 3 to 5 years of high school - it is similar in other federal states in Germany. 

Thanks for these excellent references. Because I am still reading what I find on these references, I did not answer quickly. Taylor, L. & Parsons, J. (2011). Improving Student Engagement. is really inspiring. Thanks a lot! I will be able to answer in few days as a typhoon is coming right on us. ;)